SURFACE-SWIMMING FAUNA (VERTEBRATES). 127 



considerable time under water. When they 

 come to the surface to renew the air-supply in 

 their lungs, they first make a violent expiratory 

 effort from the nostril, and drive a column of 

 spray many feet into the air above them. This 

 phenomenon is called by the whale fishers 

 "spouting," and it was erroneously supposed 

 by them to be a column of water forced from the 

 mouth into the nostril, and then expelled at the 

 surface. 



The Dolphins and the Porpoises are distin- 

 guished from the true Whales by the fact that 

 they are provided with teeth, on one or both of 

 their jaws, and there is no "whale-bone." 



The Sperm-whale has probably been called a 

 " Whale" from its enormous size, but it is 

 anatomically very widely separated from the true 

 whales and more closely allied to the Dolphins. 

 It has no "whale-bone," and the lower jaw is 

 provided with a row of sharp-pointed teeth set 

 in a groove in the bone. Its great value is due 

 to the fact that there is a large cavity situated 

 above the skull, containing an oily substance from 

 which " Spermaceti " is made. 



The principal food of these large "Toothed- 

 whales " seems to be Cuttlefishes, and the ex- 

 amination of the contents of their stomachs, 

 which has been carried out on board the Prince 

 of Monaco's private steam-ship when engaged on 

 a scientific cruise, has yielded some new forms of 

 these giant Molluscs. The Sperm-whales, how- 

 ever, do not disdain a Fish diet as well. 



The Porpoises are found on our own coasts. 

 They may often be seen following the " schools " 



